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Biomedical subjects

L Wang

Publications and source records attributed to L Wang.

At least 1,513 records · Page 84Linked to original sources
PubMed1997

[Autoradiography of NMDA receptors in amygdala-kindled rats with tolerance to and dependence on the anticonvulsant effect of clonazepam].

Mechanisms underlying tolerance to and dependence on the anticonvulsant effect of clonazepam are not clear. Autoradiography of the NMDA receptors in amygdala-kindled rats with tolerance to and dependence on the anticonvulsant effect of clonazepam was carried out. When tolerance developed, the binding of [3H] TCP (N-(1-thieny) cyclohexylpiperidine) to NMDA receptors was found to be increased at the polymorphocellular layer of the right CA1, and decreased at the molecular layer of the cerebellar ansiform lobule. On day 7 of the discontinuation of clonazepam, the binding did not change further. These changes may be responsible for the tolerance to and dependence on the anticonvulsant effect of clonazepam. However, the exact significance of these results should be further investigated.

Amygdala↗
PubMed1997

Seroprevalence of human herpesvirus-6 in healthy population in two provinces of north China.

BACKGROUND: Human herpesvirus-6 (HHV-6) infection is ubiquitous in selected population with seroprevalence of 60-80%. Little is known for that in China, except few sporadic studies. To understand prevalence of HHV-6 antibody in Chinese population, this seroepidemiological study was conducted. METHODS: Sera were collected from 430 healthy persons and donors living in North China, and tested for HHV-6 antibodies using IFA with HHV-6 GS strain passaged on HSB-2 cells as antigen, and titer equal or higher than 1:10 was regarded as seropositive. RESULTS: Of the 430 serum samples tested, 297 (69.1%) were positive for HHV-6 IgG. Both seropositive rate and GMT in females were significantly higher than those in males, with X2 = 7.05, P < 0.01 and F = 7.23, P < 0.01, respectively. Statistically significant difference in prevalence of HHV-6 antibody among various age groups was observed in both sexes, with X2 = 20.08 and 20.28, P = 0.04, respectively, and young children had a higher titer than adults. But, no significant difference in prevalence was observed in blood donors between various age groups or both sexes. CONCLUSIONS: This study suggests that HHV-6 infection with seropositive IgG is ubiquitous in North China, and its importance should be further studied.

Adolescent↗
PubMed1997

[The advances of research for cardiac contractile proteins structure and function].

Cardiac contractile proteins are the material basis of cardiac contractility. This paper introduces the Structures of two major cardiac contractile proteins: myosin and actin, especially the details of the two proteins' structure relevant to their function. At the same time, it describes the myosin and actin proteins' changes in normal and abnormal hearts so as to enrich our mind with knowledge of cardiac hypertrophy and heart failure at the molecular level.

Actins↗
PubMed1997

[Synthesis of S-9-(2,3-dihydroxypropyl)adenine (DHPA) analogs and their inhibition of S-adenosyl-L-homocysteine (SAH) hydrolase].

In order to search for new antiviral agents with high potency and low toxicity, eleven new acyclonucleosides were synthesized. Nucleic-acid bases were condensed with 3-chloro-2-methylpropene to give 5-8a. b, which were oxidized by N-methylmorpholine-N-oxide in the presence of OsO4 to give vicinal dihydroxy acyclonucleosides 1-4a.b. Four DHPA analogs have been tested for the inhibitory activities on s-adenosyl-L-homocysteine hydrolase (SAH). Only compound 1 showed some enzyme inhibitory effect with IC50 of 1.1 mmol.L-1.

Adenine↗
PubMed1997

Association of Helicobacter pylori infection with precancerous lesions and stomach cancer: a case-control study in Yangzhong County.

Previous study has raised H. pylori infection as a suspected biologic risk factor for gastric cancer. A comparative case-control study involving precancerous lesions and gastric cancer was conducted in Yanzhong county, an area with one of the highest rates of gastric cancer in China to study the relationship between the H. pylori infection and gastric cancer. Subjects in the study were all randomly selected participants of a screening program for gastric cancer sponsored by the Cancer Institute of CAMS in cooperation with Yangzhong county Hospital. Totally, 125 normal controls, 108 superficial gastritis, 111 atrophic gastritis and 110 gastric cancer patients were included in our study according to endoscopy and pathology result. Status of H. pylori infection was evaluated by measuring IgG antibody in plasma with ELISA assay. Our result showed Odds ratios of H. pylori infection were higher among gastritis and cancer groups, 4.5 (95% CI 2.5-7.9) for superficial gastritis, 6.3 (95% CI 3.4-12) for atrophic gastritis, 3.3 (95% CI 1.9-5.9) for gastric cancer. It was found in our study that consumption of pickled vegetables and drinking dirty water increased the relative risk of H. pylori infection for both precancerous lesions and gastric cancer and that H. pylori infection had higher risk of atrophic gastritis and gastric cancer for males and also higher risk of atrophic gastritis for olders. Our results strongly support the casual role played by H. pylori infection in the carcinogenic process of gastric mucosa.

Aged↗
PubMed1997

[Adhesion of erythrocytes of patients with transient ischemic attack to injured endothelial cells].

Adherence of erythrocytes of patients with transient ischemic attack(TIA) to human umbilical vein endothelial cells(HUVEC) treated with H2O2 were quantitatively studied in the flow chamber system. The results showed that injured HUVECs enhanced the adherence of erythrocytes to endothelial cells in patients with TIA. The increased adhesion of erythrocytes to endothelial cells might promote the vascular damage. Consequently endothelium might play an important role in the increased adhesiveness of TIA RBC to endothelial cells.

Aged↗
PubMed1997

[Red blood cell as a carrier of Superoxide Dismutase].

In order to prolong the in vivo half-life of Superoxide Dismutase (SOD) to improve the blood compatibility and to treat tissue injuries caused by activated oxygen during ischemia and hypoxia, erythrocytes were used as SOD carrier. The entrapment of SOD into rabbit erythrocytes was successfully employed. It demonstrated in vitro experiment that SOD activity maintained a stable level in the first 8 hours, and these erythrocytes can be stored at 4 degrees C for one week without loss of activity. The SOD carrier erythrocytes might be useful in clinical and special environmental medicine.

Animals↗
PubMed1997

[Observation on electrogastrogram changes during parallel swing stimulation].

In order to study the relationship between cutaneous electrogastrogram (EGG) and nausea syndrome of the motion sickness, power spectrum analysis is used to analyze EGG recorded during motion sickness evoked by the parallel swing in 32 healthy men. 20 subjects showed a shift of Period Dominant Frequency (PDF) of EGG from Three CPM (2.40-3.70cpm) to Tachygastria (3.70-10.00cpm). PDF, the percentage of power of Tachygastria wave and Dominant Frequency Instability Coefficient significantly increased (P < 0.01). The incidences of nausea syndrome was obvious at the moment after swing. The result showed that EGG may be used for testing nausea symptoms of motion sickness.

Electrodiagnosis↗
PubMed1997

[Quantitative method of toluol diffusive sampling].

The diffusive sampling is of great advantage to air pollutant monitoring in manned spaceflight cabin. The quantitative method and steps of diffusive sampling is given in this paper by an experimental studying on diffusive sampling of toluol-air mixture; Effectiveness of the method and effects of environmental factors on the quantification of the diffusive sampling were discussed. This method is of reference value to quantification of the polycomponent-air mixture.

Air↗
PubMed1997

[Comparison of evaluation methods on changes of facial microcirculation during induction of motion sickness].

In order to increase the accuracy of motion sickness grading criteria, infrared thermography and Laser Doppler microcirculation blood-flow detector were used in 60 healthy male individuals: before, immediately, and 20 min after paralleled-swing stimulation. Facial skin temperature and microvessel blood-flow were recorded. The results showed that facial skin temperature and blood flow in facial microvessels fell together with the appearance of pallor. However, the degree of pallor observed with naked eye was inconsistent with that found by thermography or facial blood flow. It suggests that the accuracy of grading might be improved with the use of thermography or measurement of facial microvessel blood flow.

Face↗
PubMed1997

[Anti-virus effect of hepatocyte stimulating substance (HSS) on duck hepatitis B virus in vivo].

We used one day old Beijing ducklings infected by duck hepatitis B virus as experimental model to observe anti-virus effect of HSS. Beijing ducklings hatched within one day were injected intravenously with duck hepatitis B virus (DHBV). Positive DHBV-DNA in ducklings' sera were detected 7 days later. Serum samples were obtained from all ducklings before, during and after drug treatment at different times and stored at -70 degrees C. The collected samples were detected DHBV-DNA by dot-blot hybridization test at the same time. The therapeutic effects were evaluated by OD value of dot-blot and by the inhibitory rate of DHBV-DNA. The results showed that HSS (with 50 mg/kg/day and 200 mg/kg/day) were effective in inhibition of DHBV-DNA during and after drug treatment, especially in the HSS group of large dosage. The inhibitory effect appeared early and high dynamic. The inhibitory rate of DHBV-DNA during and after drug treatment were higher than the NS group (P < 0.05). No inhibitory effect was observed in NS group. The hepatic biopsy showed HSS groups had milder damage than NS group, indicating that the HSS could inhibit the replication of DHBV-DNA in Beijing ducklings.

Animals↗
PubMed1997

[Primary study on Fas-mediated apoptosis in the liver tissue of patients with chronic hepatitis B].

Apoptosis may be the cause of cell death that activate gene due to certain factors. It has been suggested that apoptosis is mediated through Fas antigen. To evaluate the role of the Fas antigen and apoptosis in chronic hepatitis B (CHB), we observed the Fas expression and nuclear DNA fragement in CHB hepatic tissue using immunohistochemistry and TUNEL method respectively. The results showed that the Fas antigen expressing cells located mainly in inflammation infiltrating area but less in non-inflammation infiltrating area; the positive cells were found particularly among infiltrating lymphocytes at the advancing edges of "piecemeal necrosis" near the portal regions. The expression of Fas was detected mainly in the cytoplasm of hepatocytes. 46 samples from 56 CHB patients were Fas positive, the posive rate reached 82%. The Linear Correlation and Regression analysis suggested that there was a direct correlation between nuclear DNA fragement and Fas expression. These findings suggest that the apoptosis mediated through Fas antigen may play an important role in pathogenesis of CHB.

Adolescent↗
PubMed1997

[Clinical and pathological study on liver fibrosis in viral hepatitis].

49 patients with viral hepatitis were studied on the correlationship between liver fibrosis and the level of serum precollagen type III (PC III), pre-collagen III pre-peptide (P III P), Laminin (LN), hyaluronic acid (HA) and collagen type IV (IV-C), as well as relationship between them and the expression of LN, IV-C, a-smooth muscle actin (a-SMA) and cytokeration (CK) in the liver tissues examined by immunohistochemistry. Results showed that the level of PC III, P III P, LN, HA and IV-C in the groups of liver cirrhosis and chronic severe hepatitis were higher than that in the groups of acute and chronic hepatitis. High correlation was found between the level of these markers (especially the level of the IV-C) and the degree of fibrosis in the group of chronic hepatitis. So were the expression of LN, IV-C, a-SMA and CK in the liver tissue. The results also showed that the liver fibrosis correlated with inflammatory reaction in the liver. So the authors suggested that more attention should be paid to the inflammatory reaction of the liver for prevention and treatment of liver fibrosis.

Adolescent↗
PubMed1997

[In situ detection of DNA strand breaks associated with apoptosis in viral hepatitis].

The significance of apoptosis in liver injury or liver fibrosis in viral hepatitis is yet unknown. The authors investigated the hepatocyte apoptosis and the correlation between the apoptosis and the liver injury in 22 liver biopsy specimens from the patients with hepatitis. Specimens were put onto slides to detect DNA strand breaks in situ with nick end labeling method using terminal deoxynucleotide transferase and bio-11-dUTP (TUNEL). The results showed that most of TUNEL-positive hepatocytes which have the features of apoptosis were apoptotic hepatocytes. There was TUNEL-positive reaction in few of the hepatocytes with ballooning degeneration. The degree of apoptotic hepatocytes in the chronic hepatitis was stronger than that in the acute hepatitis. This suggested that the degree of apoptotic hepatocytes correlated with the chronicity of hepatitis.

Apoptosis↗
PubMed1997

[Studies on peripheral blood stem cells mobilization by short course and high-dose G-CSF].

OBJECTIVE: To explore the effect of short-course, high dose granulocyte-colony stimulating factor (G-CSF) on peripheral blood stem cell (PBSC) mobolization. METHODS: G-CSF 5microg/kg was injected subcutaneously twice daily for 3 consecutive days. On the first day and the fourth day the peripheral blood and bone marrow were collected for CFU-GM, BFU-E, CFU-mix assays and CD34/CD38 detection. A single apheresis of over 8000ml blood processing was performed with CS-3000 blood cell separator. The mononuclear cells were prepared for hematopoietic colony assays and CD34/CD38 detection before and after freezing. RESULTS: After adminitration of G-CSF, the white blood cell count increased significantly. The CFU-GM, BFU-E, CFU-mix yields and CD34+ CD38+ cell and CD34+ CD38- cells also increased significantly (P<0.05). The median of mononuclear cells was 1.56 x 10(8)/kg. After one week freezing, the recovery of mononuclear cells, CFU-GM, BFU-E yields and CD34+ CD38+ cells were about 80% (P>0.05) and CFU-mix yields was 60%; The CD34+ CD38- cells were decreased compared with that of pre-freezing (P<0.05). The median of the reinfused mononuclear cells was 1.27 x 10(8)/kg,CFU-GM 6. 7 x 10(4)/kg, BFU-E 1.6 x 10(4)/kg, CFU-mix 0.32 x 10(4)/kg, CD34- CD38+ cells 1.6 x 10(6)/kg and CD34+ CD38- cells 0.23 x 10(6)/kg. CONCLUSION: Short course and high-dose G-CSF can effectively mobilize the peripheral stem cells. The mononuclear cells, hematopoietic colonies and CD34/CD38 cells were satisfied for the peripheral stem cells rescue.

ADP-ribosyl Cyclase 1↗
PubMed1997

[Cloning and expression of heavy- and light-chain variable region genes of monoclonal antibody specific for human fibrin].

OBJECTIVE: To obtain the minimum molecule having activity to bind human fibrin. METHODS: The immunoglobulin heavy- and light-chain variable region (VH and Vkappa) genes were isolated from 8E5 hybridoma cells, which secreted a monoclonal antibody against human fibrin, by RT-PCR. An expression vector pOPE51-8E5 was constructed for the recombinant VH-Vkappa expression. The transformed E. coli JM 109 cells were propagated and induced by IPTG. RESULTS AND CONCLUSION: Expression product was found in the periplasmic space and inclusion bodies by SDS-PAGE and immunobloting. It was a 30000 single chain fragment (scFv) with antigen-binding specificity. The yield of the scFv was 28.9% of the total bacterial proteins.

Animals↗
PubMed1997

[Preliminary study on oncogene MDM2 in acute leukemias].

OBJECTIVE: To explore the causes of MDM2 gene overexpression. METHODS: The amplification and overexpression of MDM2 gene in 41 acute leukemia patients and two leukemic cell lines (K051 and HL60) were studied by using Southern blot, dot hybridyzation and RT-PCR techniques. RESULTS: Overexpression of MDM2 gene was found in 51.2% (21/41) of the patients and HL60 cell line, but no amplification of the gene was found in all the patients and the two cell lines. CONCLUSION: The level of MDM2 gene expression was related to the prognoses of the patients but not to FAB subtypes of acute leukemias.

Actins↗